1. Field of the Invention
Generally, the field of the present invention is solid state lasers. More particularly, the present invention relates to unstable OPO resonators emitting beams having superior beam quality.
2. Background
Reliability and accuracy requirements in the laser rangefinder arts have stimulated active development in the laser rangefinder arts for some time. Many notable breakthroughs have made it possible for laser rangefinders and related laser systems to be used in increasingly rugged environments while operating at increasingly heightened specifications. For example, in U.S. Pat. No. 6,373,865 to Nettleton et al. a pseudo-monolithic laser with an intracavity optical parametric oscillator provides the functionality of many ordinarily difficult-to-package discrete optical components, each with associated optical mounts, through an easy assembly that may be permanently adjusted in a very short amount of time. In U.S. Pat. No. 7,532,650, also to Nettleton et al., another significant advance to monoblock type systems came with the inclusion of a convex lens for improved beam quality.
However, beam quality remains relatively poor, resulting in heightened mechanical requirements, such as larger lenses and apertures, contributing detrimentally to system size, weight, and overall functionality. Thus, a need remains for a lightweight and easy to manufacture laser system that can provide improved beam quality at farther distances.